[oceanplexian]

I think that your heart is in the right place with a message like this, but my feedback would be to keep it shorter, perhaps to a paragraph or two. There is a phrase called “the message is the medium” and I think it applies to hiring.

The best way to reject a candidate IMO is to call the candidate, deliver short feedback over the phone “Some of the feedback we got from the interviewers was we like to see the problem solved in a shorter amount of time/ less space complexity/ whatever). If I was on the fence, I would them know that if they want to try again they can give it another shot in 6 months, a year, whatever. To me this seems like the most humane way to do it (This was actually my experience with Google, maybe 8-10 years ago).